Pair (doublet) is par declined as the masculine noun grad (town). Corresponding subjects are in genitive plural.
example: Imaju tri pary obuvij. = I have three pairs of shoes.

All kind of containers or similar concepts are expressed in the same way as pairs. Corresponding subjects are in genitive plural.
example: Imaješ jedin buket květov. = You have one bouquet of flowers.

One half is polovina declined by the feminine noun pattern žena (woman). Corresponding subjects are in genitive singular.
example: polovina hlěba = one half of bread.

Other fractions (1/3, 1/4, ...) are made from ordinal numbers by adding suffix -ina and are declined by the feminine noun pattern žena (woman). Corresponding subjects are in genitive singular.
example: četvrtina hlěba = one fourth of bread.

Decimal numbers have točka (decimal point). This word originally means any point and is declined by the feminine noun pattern žena (woman), but in decimal numbers it has always the same form točka.
example: 3.14 = tri točka četyrinadset.